Personally, I believe that watering the lawn and irrigation practices, in general, tend to overwhelm people with what I’ve always called “Analysis Paralysis.” When they don’t get a one-size-fits-all answer, they go into shutdown mode because they simply don’t want to think about it. But fear not, dear reader! I have compiled a tip sheet that covers the burning question: “How much and how often should you water your grass?”
Unfortunately, the answer isn’t always as straightforward as the question itself. In Southeast Texas, irrigation and watering needs are dependent on several factors: the type of grass you have, your soil profile, mowing height, the kind of irrigation or sprinkler system you use, and, of course, Mother Nature’s whims.
The Right Amount for the Right Temperature
Let’s start with a basic irrigation schedule that takes into consideration temperatures and rainfall. Normally, turf and landscapes in this area do fine with 1-1½ inches per seven-day week when daytime temperatures are in the 70s and 80s. As the mercury rises to 88-92 degrees, you can probably up that to 1-1½ inches every four to five days. When temperatures consistently exceed 93 degrees (usually July-August), you should water every two to three days.
The Magic of Compost
Here’s a golden nugget of knowledge I’ve gathered over the past 15 years—adding more compost as a top dressing can make your lawns and landscapes more drought-tolerant. In other words, the more organically-enriched the soil is, the less water you need. I know several colleagues in the soils business who haven’t run their irrigation systems during mini-droughts thanks to this clever technique.
Grass Matters
The type of grass you have also plays a crucial role in determining watering needs. St. Augustine needs the most water, Bermuda comes next, and Zoysia requires far less than the previous two. However, the most critical factor is your soil. Clay or sandy soils that lack organic matter tend to dry out quickly and require more water. This is where adding organic matter, such as the compost mentioned earlier, becomes essential.
Timing Is Everything
Now, let’s talk about the “when.” I always recommend watering early in the morning. That’s when water pressure is at its best, there’s less wind to evaporate the moisture, and the turf will have a reserve of water for the warm day ahead. If you have an automatic sprinkler system, schedule it to run between 3 and 8 a.m. If you don’t have an automatic system, start the sprinkler when you first wake up. Avoid watering at night to prevent fungal diseases like brown patch.
Measure Your Time
Determining how long it takes for your system to put out an inch of water is key. Place an empty tuna or cat food can at the farthest point the spray pattern reaches. When it fills up, that’s how long it takes. Depending on the system, the time can range from 15 to 45 minutes. If it seems like some of your neighbors don’t run their sprinklers as much as you, it could be because they have more organic matter in their soil. Just a friendly reminder: Rich, organic soil takes time to develop—consistently adding compost, enriched topsoil, or soil activators each year is crucial.
Mow It Tall, Be the Envy of All
Here’s a simple yet effective strategy: adjust your lawnmower to the tallest setting possible—unless you have Bermuda or thin-blade Zoysia. Tall grass in good soil develops deeper roots that draw more moisture from the depths, reducing the need for supplemental irrigation. Additionally, lawns mowed tall provide shade. For instance, Bermuda is a low-profile grass, so shading it out with St. Augustine will prevent it from spreading aggressively.
The Exception: Newly Sodded Lawns
Now, let’s address the exception to all the above advice. Newly sodded lawns require daily watering during the heat of summer. Keep the soil under the root zone moist, allowing the roots to establish themselves in the soil below. Avoid drowning the new sod—just keep it moist enough to soften the soil and help the roots grow.